Tuesday, March 16, 2004

Anyone wondering if spring has really arrived has only to spend a few minutes outdoors listening to the abundant bird songs. Avian vocalization has increased considerably during the last few weeks, so it is impossible not to notice. Perhaps our northern cardinal was the first to speak out, but several of the other full-time residents were not far behind. Now, any wooded area in the Coastal Bend rings of songs by chickadees, titmice, wrens, jays, mockingbirds, and doves.

Most folks pay little attention, and when asked to identify even the most common bird songs, readily admit they are birdsong challenged (I believe that is the current appropriate term). But yet, it would surprise those same individuals how many bird songs they already know. For instance, who doesn't recognize the "bob-white" song of a bobwhite quail, the "fee-bee, fee-bu" song of a Carolina chickadee, the "jay, jay, jay" song of a blue jay, or the "what, cheer, cheer, cheer, cheer, cheer, whot, whot, whot," or "birdy, birdy, birdy" song of the northern cardinal. And what about the "caw" of a crow or "teakettle" of a Carolina wren?

Birdsong can be difficult for even the avid birder. Even those of us who have been enjoying birdsong for many years can have problems in spring, especially when the neotropical migrants begin to arrive. Songs not heard since last year, or for several years for some species, can be difficult. Others can be easily recalled. The "pee-ah-wee, pee-err" of the Eastern wood-pewee, for instance, can hardly be mistaken. Warbler songs require an extra good memory to be able to identify each in spring. Although a few, such as that of a northern parula, is so distinct that the first song each spring is easily recognized. And what about the high-pitched calls of cedar waxwings?

The vast majority of South Texas birds possess a song, although fewer than half of the almost 9,500 known bird species actually sing. But many species possess a repertoire of songs, often singing different songs in order, one after the other. Our northern mockingbird has as many as 150 songs, while a brown thrasher can sing more than 3,000 song types. A European starling's repertoire may include as many as 67 song types. And many wrens, especially the tropical wrens, often sing duets, so that one individual begins the song and its mate ends the song.

Although most birds learn only the songs they hear from their own species, the mockingbird is an exception. It is estimated that only about 85 percent of a mockingbird's singing are "uniquely mockingbird," while the other 15 percent are derived from all types of sources. Those can include other nearby birds, a human baby's cry, an engine, a whistle, and an amazing assortment of other sounds. They rarely imitate extensive sounds, but rather simplify a phrase by utilizing only pieces. Mockers often imitate cardinals but seldom if ever imitate the more detailed and extensive songs of wrens.

How many songs do birds sing in a single day? That varies with the species. Ornithologist Margaret Nice recorded 2,035 songs in a single May day for a song sparrow. She also reported a black-throated green warbler that sang 1,680 songs in seven hours, and she estimated that on a typical day of 16 daylight hours he would have sung more than 3,000 songs. But the North American winner is the red-eyed vireo. Ornithologist Harold Mayfield recorded a Michigan red-eye which sang 22,197 songs in a day.

Biologists tell us that bird songs are utilized to identify the bird's territory, usually directed at other males, and to attract a mate. The song may also serve to convey a message. But whatever their purpose, most listeners appreciate birdsong simply for their acoustical quality. For many of us, it would be an empty world without the songs of birds. And who could enjoy a fresh spring day without birdsong?